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相关论文: The Steep Price of No Hair in a Modified Loop Quan…

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We study the dynamics of the Bianchi I universe in modified loop quantum cosmology (mLQC-I) and uncover a robust mechanism for isotropization: the shear is dynamically suppressed after the bounce and decays rapidly in the quantum…

广义相对论与量子宇宙学 · 物理学 2026-05-26 Wen-Cong Gan , Leila L. Graef , Rudnei O. Ramos , Gustavo S. Vicente , Anzhong Wang

In homogeneous and isotropic loop quantum cosmology, gravity can behave repulsively at Planckian energy densities leading to the replacement of the big bang singularity with a big bounce. Yet in any bouncing scenario it is important to…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Dah-Wei Chiou , Kevin Vandersloot

In arXiv:2603.18175, the authors argue, based on numerical studies of particular cases, that the quantum damping of cosmological shear in a modified loop quantum cosmological model (mLQC-I) that was recently found in arXiv:2510.14021 is not…

广义相对论与量子宇宙学 · 物理学 2026-04-13 Wen-Cong Gan , Leila L. Graef , Rudnei O. Ramos , Gustavo S. Vicente , Anzhong Wang

Anisotropies generically dominate the earliest stages of expansion of a homogeneous universe. They are particularly relevant in bouncing models, since shears grow in the contracting phase of the cosmos, making the isotropic situation…

广义相对论与量子宇宙学 · 物理学 2020-09-04 Ivan Agullo , Javier Olmedo , V. Sreenath

In a wide class of cosmological models, a positive cosmological constant drives cosmological evolution toward an asymptotically de Sitter phase. Here we connect this behavior to the increase of entropy over time, based on the idea that de…

高能物理 - 理论 · 物理学 2018-03-06 Sean M. Carroll , Aidan Chatwin-Davies

We show that it is possible to realize a cosmological bouncing solution in an anisotropic but homogeneous Bianchi-I background in a class of non-local, infinite derivative theories of gravity. We show that the anisotropic shear grows slower…

广义相对论与量子宇宙学 · 物理学 2021-07-20 K. Sravan Kumar , Shubham Maheshwari , Anupam Mazumdar , Jun Peng

The comprehensive formulation for loop quantum cosmology in the spatially flat, isotropic model was recently constructed. In this paper, the methods are extended to the anisotropic Bianchi I cosmology. Both the precursor and the improved…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Dah-Wei Chiou

In classical Bianchi-I spacetimes, underlying conditions for what dictates the singularity structure - whether it is anisotropic shear or energy density, can be easily determined from the generalized Friedmann equation. However, in…

广义相对论与量子宇宙学 · 物理学 2022-12-29 A. Meenakshi McNamara , Sahil Saini , Parampreet Singh

The big bang singularity could be understood as a breakdown of Einstein's General Relativity at very high energies. Adopting this viewpoint, other theories, that implement Einstein Cosmology at high energies, might solve the problem of the…

广义相对论与量子宇宙学 · 物理学 2015-06-15 Jaume Amorós , Jaume de Haro , Sergei D. Odintsov

The detailed formulation of loop quantum cosmology with higher order holonomy corrections has been constructed recently in the homogeneous and isotropic spacetime, yet it is important to extend the higher order holonomy corrections to…

广义相对论与量子宇宙学 · 物理学 2015-06-12 Xiao-Jun Yue , Jian-Yang Zhu

We investigate the $\phi^2$ inflationary model in the Bianchi-I spacetime using effective spacetime description of loop quantum cosmology to understand the issues of the resolution of initial singularity, isotropization, effect of…

广义相对论与量子宇宙学 · 物理学 2013-07-11 Brajesh Gupt , Parampreet Singh

In this paper, we first provide a brief review of the effective dynamics of two recently well-studied models of modified loop quantum cosmologies (mLQCs), which arise from different regularizations of the Hamiltonian constraint and show the…

广义相对论与量子宇宙学 · 物理学 2021-06-25 Bao-Fei Li , Parampreet Singh , Anzhong Wang

We study anisotropic Bianchi-I cosmology, incorporating quantum gravitational corrections into the Einstein equation through the scale-dependent Newton coupling and cosmological term, as determined by the flow equation of the effective…

广义相对论与量子宇宙学 · 物理学 2025-12-03 Chiang-Mei Chen , Akihiro Ishibashi , Rituparna Mandal , Nobuyoshi Ohta

The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using…

广义相对论与量子宇宙学 · 物理学 2017-06-20 Peter Diener , Brajesh Gupt , Parampreet Singh

The "improved dynamics" of loop quantum cosmology is extended to include anisotropies of the Bianchi I model. As in the isotropic case, a massless scalar field serves as a relational time parameter. However, the extension is non-trivial…

广义相对论与量子宇宙学 · 物理学 2010-04-14 Abhay Ashtekar , Edward Wilson-Ewing

We present a systematic study of the cosmological dynamics resulting from an effective Hamiltonian, recently derived in loop quantum gravity using Thiemann's regularization and earlier obtained in loop quantum cosmology (LQC) by keeping the…

广义相对论与量子宇宙学 · 物理学 2018-04-25 Bao-Fei Li , Parampreet Singh , Anzhong Wang

The detailed formulation for loop quantum cosmology (LQC) in the Bianchi I model with a massless scalar field was recently constructed. In this paper, its effective dynamics with the LQC discreteness corrections is studied and the equations…

广义相对论与量子宇宙学 · 物理学 2007-09-12 Dah-Wei Chiou

We construct and study Loop Quantum Cosmology (LQC) when the Barbero-Immirzi parameter takes the complex value $\gamma=\pm i$. We refer to this new quantum cosmology as complex Loop Quantum Cosmology. We proceed in making an analytic…

广义相对论与量子宇宙学 · 物理学 2015-06-22 Jibril Ben Achour , Julien Grain , Karim Noui

We consider the introduction of anisotropy in a class of bouncing models of cosmology. The presence of anisotropy often spells doom on bouncing models, since the energy density due to the anisotropic stress outweighs that of other matter…

广义相对论与量子宇宙学 · 物理学 2022-01-27 Karthik Rajeev , Vikramaditya Mondal , Sumanta Chakraborty

With the non-metricity scalar $Q$ as the functional argument, several $f(Q)$ gravity models are found to be proposed which are perfectly able to mimic the late-time accelerated expansion as pointed out by the type Ia supernovae…

广义相对论与量子宇宙学 · 物理学 2026-02-03 Subhajit Pal , Atanu Mukherjee , Ritabrata Biswas , Farook Rahaman
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